I'm working on two different files. The first one is the same shape as Yukon Jack's push bar.
http://yuk0njack.com/70blazer/brushguard/p3210345.jpg
The second one is much shorter and won't hide the Chev logo on the grille, and looks kinda like Lieferson's except the top bar is a couple inches lower.
http://67-72chevytrucks.com/vboard/attachment.php?attachmentid=1643942&stc=1&d=1492633031 This is probably the one I will finally build. I also played around with the frame mounting area so that the factory oval hole can be used for mounting. I still need to cut a full size template to make sure everything mounts properly.